Our interdisciplinary group at The Pennsylvania State University has developed a pneumatic artificial heart. The heart is FDA approved for, and has had limited use as, a bridge to cardiac transplantation. Issues regarding clinical use center around potential for hemolysis (not problematic in calf studies), optimal valves (Bjork-Shiley convexo- concave values are no longer available), thrombus that forms at the suture line between the natural atrium and the atrial cuff, and pump size (for smaller patients). We propose to evaluate hemolysis mechanisms, and alternate prosthetic valves and to compare atrial cuff materials. We recently completed the design and fabrication of a clinical heart for use in smaller patients. We propose to perform appropriate animal implant studies to evaluate this heart. Satisfactory completion of this phase of the research will reduce blood damage and reduce the risk of thromboembolism associated with the artificial heart and will provide a second size artificial heart to encompass a broader range of patients. Also included in the proposed work scope is a protocol for the continued clinical use of the artificial heart as a bridge for transplantation in appropriately selected patients (1 patient/year). Spectacular progress is being made in the electric heart being developed through this grant. Recent animal survival has been extended to 13 months with minimal device wear observed. We now propose a series of logical advances to achieve a system that will be optimal for clinical use (i.e. - implanted electronics, implantable battery, a minimal diffusion compliance chamber, wireless electrical energy transmission via inductive coupling and wireless transmission of messages to and from the heart). The use of hybrid bearings for increased life and performance will be evaluated. Motor Hall sensors will be relocated to reduce device size and ease assembly. Control system enhancements to reduce power consumption and eliminate Hall sensors entirely will be investigated. Engineering studies include bench testing, fluid mechanics, and reliability testing. Chronic animal implant studies, using the well- understood, reliable bovine model, will include detailed hematologic evaluation, and control system evaluation during rest, exercise and pharmacologic intervention. Satisfactory completion of this project will result in a useful artificial heart having a two year functional life, which will be a useful therapeutic tool in certain patients with end- stage heart disease who are not able to have heart transplantation.